today president obama repeated his promise to bring the killers to justice. he also said the people of boston is proof that americans will prevail. listen. >> the american people refuse to be tore rerrorized. because what the world saw yesterday, the aftermath of the explosion, are stories of heroism, kindness, generosity and love. >> i looked down and there was actually a person who was bleeding on the street. they were right off the sidewalk just laying down. luckily this restaurant was helping them and it was great to actually see people teaming up together to help the people that were in need. >> exhausted runners who kept running to the nearest hospital to give blood, and those who stayed to tend to the wounded, some tearing off their own clothes to make tourniquets. the first responders who ran into the chaos to save lives. >> you see on the video now all these guys jumping over fences trying to help out. people activated immediately, whether they were volunteers or the boston police. >> the men and women were still treating the wounded at some of the b